Technical Field
The present disclosure generally relates to the field of transfer of thermal energy and, more particularly, to removal of thermal energy from electrically-driven devices in close proximity.
Description of the Related Art
There are many applications, ranging from consumer electronics to telecommunications and the like, in which electrically-driven devices (e.g., semiconductor-based integrated circuits) capable of performing various tasks are packed in close proximity in a small form factor to serve various needs. Such electrically-driven devices may include, for example, driver circuits, logic processors, graphics processors, laser diodes including edge-emitting lasers and vertical-cavity surface-emitting lasers (VCSELs), light-emitting diodes (LEDs), photodiodes, sensors, etc. Many of such electrically-driven devices inevitably generate thermal energy, or heat, in operation. As the number and complexity of the functionalities performed by such electrically-driven devices continue to increase and as the distance between electrically-driven devices in the small form factor continues to decrease, heat generated by such electrically-driven devices present some technical challenges that need to be addressed.
For one thing, performance, useful lifespan, or both of an electrically-driven device may be significantly impacted if the heat generated by the device is not adequately dissipated or otherwise removed from the device. Moreover, given the close proximity between two or more electrically-driven devices in some applications, a phenomenon of thermal coupling between the two or more devices may occur and result in the heat generated by one of the devices being transferred to one or more adjacent devices. More specifically, when thermal coupling occurs and when an adequate heat transfer mechanism is lacking, heat generated by electrically-driven devices in close proximity may detrimentally deteriorate the performance and useful lifespan of some or all of the affected devices.
Many metal-based heat dissipation or cooling packages, whether water-cooled or air-cooled, have been developed for use in compact form factor to dissipate heat generated by electrically-driven devices in small form factors. For instance, heat exchangers and heat pipes made of a material with high thermal conductivity, such as copper, copper-tungsten alloy, aluminum or iron, for example, are commercially available. However, most metal-based heat exchangers and heat pipes tend to experience oxidation, corrosion and/or crystallization after long periods of operation. Such fouling factors significantly reduce the efficiency of heat transfer of metal-based cooling packages. Other problems associated with metal-based cooling packages include, for example, difficulty in precision alignment in mounting laser diode bars, VCSELs, LEDs or chips in laser diode/VCSEL/LED cooling applications, issues with overall compactness of the package, corrosion of the metallic material in water-cooled applications, difficulty in manufacturing, high-precision fabrication, electrical isolation, etc. Yet, increasing demand for higher power density in small form factor motivates the production of a compact cooling package with fewer or none of the aforementioned issues. Moreover, conventional packages typically use wire bonding to provide electrical power to the electrically-driven device(s) being cooled, but wire bonding may add cost and complexity in manufacturing and may be prone to defects in addition to occupying space unnecessarily.